Carpal Instabilities Definition by IFSSH Orthopaedic Hand Conference Wrist is unstable only if it exhibits • symptomatic dysfunction Bernard F. Hearon, M.D. inability to bear loads Clinical Assistant Professor, Department of Surgery • University of Kansas School of Medicine - Wichita May 7, 2019 • abnormal carpal kinematics Garcia-Elias, JHS 1999 Carpal Instability Mayo Classification CID - Dissociative Wright, JHS (Br) 1994 Instability within carpal row usually due to intrinsic ligament injury • Carpal Instability Dissociative (CID) • Carpal Instability Non-Dissociative (CIND) • Scapholunate dissociation • Carpal Instability Adaptive (CIA) • Lunotriquetral dissociation • Carpal Instability Complex (CIC) • Scaphoid fracture Carpal Instability Carpal Instability CIND - Nondissociative Instability between carpal rows due CIA - Adaptive to extrinsic ligament injury Extra-carpal derangement causing carpal malalignment • CIND - Volar Intercalated Segment Instability (VISI) Midcarpal instability caused by malunited • CIND - Dorsal Intercalated fractures of the distal radius Segment Instability (DISI) Taleisnik, JHS 1984 • Combined CIND Carpal Instability Carpal Instability CIC - Complex Instability patterns with qualities of both CID and CIND patterns • Dorsal perilunate dislocations (lesser arc) Perilunate • Dorsal perilunate fracture-dislocations (greater arc injuries) Instability • Volar perilunate dislocations • Axial dislocations, fracture-dislocations Carpal Instability Carpal Instability Perilunate Dislocations Mayfield Classification Progressive Perilunar Instability • Uncommon, 7% of all carpal injuries • High-energy axial load (MVA, fall from height, I - Rupture SLIL, RSCL contact sports) • • II - CL dissociation • Mechanism - Hyperextension, ulnar deviation, intercarpal supination (Mayfield, 1980) • III - Rupture LTIL, dorsal carpal dislocation Present w/wrist pain, swelling, limited motion • IV - Palmar lunate dislocation (LRL & SRL • ligaments intact) • Dx often missed, radiographs misinterpreted Carpal Instability Carpal Instability Greater or Lesser Arc Injuries Imaging • Perilunate injuries may involve bones, ligaments or both • PA XR - Disruption Gilula’s arcs • Greater arc injuries include fractures of scaphoid, Lateral XR - Loss of carpal colinearity capitate (slower force application) • CT scan to assess carpal fractures • Lesser arc injuries involve ligaments only (more • rapid force application) Carpal Instability Carpal Instability Immediate ORIF for Best Result Closed Reduction Volar, Dorsal or Combined Approach • Volar - release carpal canal, reduce lunate, • Prompt reduction to decompress median repair LTIL and volar capsule (space of Poirier) nerve in carpal canal • Dorsal - restore carpal alignment, repair SLL, • IV sedation in emergency room setting address carpal fractures, repair DRCL • Longitudinal traction for 5-10 minutes • K-wire stabilization of SL, LT and midcarpal reductions • Dorsal-directed pressure on lunate with wrist palmar flexion • Suture anchors for capsular repair, capsulodesis Carpal Instability Carpal Instability Perilunate Dislocations & Transscaphoid Perilunate Fx–Disl: 10-Year Follow-Up Perilunate Summary Forli et al., JHS 2010 35A: 62-68 • Goal is stable wrist, minimal pain, functional arc of motion • Retrospective review 18 pts, avg 13-yr F/U • Most patients will not regain normal motion • Mayo score - 5 exc, 3 good, 7 fair, 3 poor or grip strength • Radiographic arthrosis observed in 12 pts • If diagnosis missed in patient < 30 yrs, ORIF should be attempted • Post-traumatic arthrosis well-tolerated • Older patients more than 4 wks post-injury • Therapeutic Level IV study (France) should have salvage proximal row carpectomy Carpal Instability Reading List Carpal Instability Scapholunate Interosseous Ligament Scapholunate • Prime stabilizer SL joint • C-shaped 3-part ligament Instability - Dorsal is thickest, strongest - Palmar is thinner, weaker - Proximal is thin, weakest • Secondary stabilizers are RSC, DRC, DIC, ST ligaments Carpal Instability Carpal Instability Acute Scapholunate Injury Natural History • FOOSH mechanism with wrist in extension, • Secondary stabilizers stretch leading to DISI ulnar deviation, supination • Lunate extends, scaphoid flexes with wrist RD • Rarely present acutely < 6 weeks from injury • Abn wrist mechanics over time leads to SLAC • Pain with wrist loading such as push-ups • Radioscaphoid, then capitolunate arthrosis • Focal swelling, tenderness at SL interval • Timely rx SL dissociation may prevent SLAC • Positive scaphoid shift test (if tolerated) Carpal Instability Carpal Instability Scaphoid Shift Test Kinematics of the Scaphoid Shift Test Wolfe et al., JHS 1997; 22A: 801-06 • Apply pressure to scaphoid tuberosity as wrist is 25 uninjured subjects (50 wrists) examined moved from ulnar to radial deviation • • 36% subjects had positive scaphoid shift test • SLIL tear allows scaphoid proximal pole to subluxate dorsally wrt scaphoid fossa • Dorsal and axial displacement correlated with positive test • Release pressure, scaphoid reduces into scaphoid fossa with reduction “clunk” • Positive test results should be confirmed by fluoroscopic exam Carpal Instability Carpal Instability Reading List Imaging Radiographic Findings • PA projection • XR - PA, lateral, scaphoid views (UD) - SL interval widened XR - bilateral clenched pencil views - SL asymmetry • - Triangle lunate • MRI - high-resolution, small-field - Scaphoid ring sign technique • Lateral projection - Increased SL angle >70 degrees Carpal Instability Carpal Instability Wrist Arthroscopy Geissler Classification • I - redundant ligament, no tear, occult instability Gold standard for diagnosing SLIL injury • • II - partial tear (proximal, volar), minimal gap, • Better sensitivity & specificity vs MRI, MRA predynamic • Permits injury classification (Geissler) • III - partial tear, articular incongruence, moderate gap, dynamic instability • Allows diagnosis concomitant pathology Able to treat partial SLIL arthroscopically • IV - complete tear/dissociation, gross static • instability Geissler, JBJS 1996 Carpal Instability Carpal Instability Treatment Considerations Prognostic Factors Is the dorsal SLIL intact? Age of Patient Stage of Injury • Young - > 30 yrs Predynamic • If dorsal SLIL disrupted, can it be repaired? Middle - 30-60 yrs Dynamic (mid-substance vs avulsion) Older - > 60 yrs - Repairable • Are the secondary scaphoid stabilizers intact? - Not repairable (rotatory subluxation) Age of Injury Static Acute - < 3 wks - Reducible • Is the carpal malignment easily reduced? Subacute - 3-6 wks - Not reducible • What is the status of the articular cartilage? Chronic - > 6 wks Arthrosis (radiocarpal and midcarpal joints) Garcia-Elias, JHS 2006 Carpal Instability Carpal Instability • Benign neglect Basis for Treatment • Intermittent splinting • Arthroscopic debridement • Symptom severity Treatment • Arthroscopic thermal annealing • Degree of instability (predynamic, Options • Arthroscopic reduction & pinning dynamic, static) • Open reduction & repair • Chronicity (acute, subacute, chronic) • Open reduction & capsulodesis • Arthroscopic findings (Geissler grade) • Open reduction & association • Open reduction & reconstruction Combined procedures Carpal Instability Carpal Instability • Arthroscopic Debridement Alone ARIF: Arthroscopic for Intercarpal Ligament Tears Reduction Internal Fixation Weiss et al., JHS 1997; 22A: 344-49 • Group I - < 3 months sx, < 3 mm increase • 127 pts w/wrist pain had arthroscopic SL interval - 83% improved debridement of ICL tears, early wrist motion • Group II - > 3 months sx, > 3 mm increase • 85% w/partial SLIL tears improved, 66% with in SL interval - 53% improved complete tears improved • Worse prognosis for older injury, wider gap • For LTIL, 100% w/partial, 78% w/complete • ARIF recommended for Group I patients tears improved Whipple, Hand Clinics 1995 • Majority pts improve w/debridement alone Carpal Instability Carpal Instability Reading List Partial SLIL Injuries Rx With Arthroscopic Radiofrequency Thermal Shrinkage Debridement and Thermal Shrinkage Darlis et al., JHS 2005; 30A: 908-14 • Thermal probe denatures collagen at 70°C • 16 pts (mean age 34 yrs) w/partial SLIL tears • Effective for rx Geissler I and II • Rx arthroscopic thermal shrinkage volar & • Long-term effect on instability unknown proximal portions of ligament, early motion • Outflow portal avoids thermal necrosis • Mean F/U 19 months, 14 pts good pain relief, 2 were unchanged • Contraindicated for pts w/pacemakers • Longer follow-up needed to establish efficacy Sotereanos, JHS 2009 Carpal Instability Reading List Carpal Instability Open Treatment Postoperative Protocol of Acute SLIL Tear • Short-arm splint/cast immobilization x 6 wks • Dorsal approach, PIN neurectomy • Removable short-arm orthosis x 6 wks Plan for dorsal capsulodesis • • Remove K-wires and allow motion at 12 wks Create bed for SLIL repair on lunate • • Strengthening initiated at 4 to 4.5 months Carpal reduction, K-wire stabilization • • Unrestricted activity allowed at 6 months • SLIL repair, dorsal capsulodesis Carpal Instability Carpal Instability RASL: Long-term Follow-up of Recon Contraindications Technique for Chronic SL Dissociation White et al., ASSH 2010 • SL subluxation NOT easily reduced 36 pts (1991-2008), avg age 50 yrs, F/U 6.4 yrs • Lunate is NOT stable (carpal ulnar • translocation) • Majority reported improved pain, function Cartilage is NOT normal • Flexion-extension arc 80% preserved • • Grip & pinch strength comparable